Building Science

71 Ways to Make Your Building More Energy Efficient

An energy efficient building reduces main­te­nance and utility costs, but, in many cases, improves dura­bil­i­ty, lessens noise, increases comfort and creates a healthy and safe indoor envi­ron­ment. A further goal of energy efficient con­struc­tion is to limit damage to the ecosystem and reduce the use of natural resources like energy, land, water, and raw materials. Reducing energy con­sump­tion is crucial because it means fewer emissions of green­house gases, a known cause of global warming. Energy efficient measures can be inte­grat­ed into new con­struc­tion or retro­fit­ted into an existing building. For­tu­nate­ly, there are many methods, materials, and resources to help designers, archi­tects, con­trac­tors and building owners move towards creating an energy efficient and high-per­for­mance building.

Energy Efficient Techniques in New Construction

New con­struc­tion gives archi­tects, con­trac­tors and building owners the oppor­tu­ni­ty to design and build an energy efficient building, and even a net-zero energy project. A net-zero energy building consumes less than or equal to the amount of energy that it produces on site through renewable resources. The steps for con­struct­ing a modern energy efficient structure begin with choosing a site and imple­ment­ing a detailed, holistic design plan. 

Site Selection and Placement of an Energy Efficient Building 

1. Ensure that public trans­porta­tion is available and local shopping is nearby. Limiting travel time and the use of private trans­porta­tion will reduce wear and tear on vehicles and save gas.

2. Build near existing infra­struc­ture to save money and resources. 

Design of an Energy Efficient Building

3. Imple­ment­ing a whole-building systems approach to new con­struc­tion is the most efficient way to achieve an energy efficient building. The whole-building approach treats the building as one energy system with separate, but dependent parts. Each part affects the per­for­mance of the entire system (the whole-building).

4. The design should make efficient use of water and elec­tric­i­ty and other natural resources and energy sources.

5. To minimize waste and materials, choose the smallest possible building for the intended application.

6. The design should strive to meet the Energy Star require­ments for sus­tain­abil­i­ty, the Lead­er­ship in Energy and Envi­ron­men­tal Design (LEED) standards, and the Inter­na­tion­al Green Con­struc­tion Code (IgCC).

7.The design of an energy efficient building should easily allow for future retrofits without impacting the per­for­mance of the building.

8. The design should take into con­sid­er­a­tion building ori­en­ta­tion. The way a structure is situated on a site and the placement of windows, rooflines and other features is critical for efficiency.

9. The design of an energy efficient building should be sus­tain­able. A sus­tain­able design aims to lessen depletion of critical resources like land, water, energy, and raw materials. Sus­tain­able design of facil­i­ties and infra­struc­ture also averts the destruc­tion of the ecosystem.

10. Utilizing an energy modeling software is an effective way to estimate a build­ing’s energy use. The model’s output can help archi­tects, con­trac­tors, and building owners modify a building per­for­mance and cost before con­struc­tion starts. 

Wall Assembly of an Energy Efficient Building

11. A con­tin­u­ous layer of insu­la­tion (CI) around the building envelope is essential to an energy efficient building. Con­tin­u­ous insu­la­tion increases the effective R‑value of the structure, elim­i­nates con­den­sa­tion, and creates a com­fort­able space for the building’s occupants. The American Society of Heating, Refrig­er­at­ing and Air-Con­di­tion­ing Engineers (ASHRAE 90.1) and the Inter­na­tion­al Energy Con­ser­va­tion Code (2015 IECC) also require con­tin­u­ous insu­la­tion in most applications.

12. For wood-framed con­struc­tion, provide more space for insu­la­tion between interior and exterior walls by utilizing 2X6 studs instead of 2X4 studs.

13. For wood-framed con­struc­tion, use a high-quality insu­la­tion like spray foam insu­la­tion. Spray foam insu­la­tion can provide an air barrier and is a far superior insu­la­tion method over a less expensive insu­la­tion material like batts and blankets.

14. Because tightly sealed, energy-efficient, wood-frame buildings are vul­ner­a­ble to moisture accu­mu­la­tion in the wall cavities, the exterior of the building must be wrapped in a water-resistant and breath­able material. Moisture in a build­ing’s walls is serious because moisture can lead to wood rot (caused by fungi) and expensive repairs. Moisture may also cause the growth of mold, which is unhealthy to the occupants of the structure. It is essential that a wood-frame building envelope controls moisture entry, accu­mu­la­tion, and removal.

15. An energy efficient wood-framed building utilizes advanced house framing (also known as optimum value engi­neer­ing). Advanced house framing reduces lumber use and waste and improves the energy effi­cien­cy of a wood-framed house.

16. Struc­tur­al insulated panel (SIP) can save up to 50 percent in energy costs. SIPs are made from a layer of foam insu­la­tion placed between pieces of plywood, strand board or cement panels.

17. To create an energy efficient concrete structure, utilize concrete wall systems with integral insu­la­tion made of expanded poly­styrene insu­la­tion (EPS) or other insu­lat­ing foam. Insulated concrete forms and insulated concrete blocks form a layer of con­tin­u­ous insu­la­tion, sub­stan­tial­ly elim­i­nat­ing thermal bridging through the wall. The Bautex Block Wall System is an example of an insulated concrete block wall system that provides a con­tin­u­ous insu­la­tion R‑value of 14, far exceeding 2015 IECC recommendations.

18. For concrete con­struc­tion, apply an air and moisture barrier to the exterior face of the concrete wall. Fully adhered membranes and fluid applied air and moisture barriers like the Bautex Air and Moisture Barrier work well with concrete con­struc­tion. Air tightness of a building has a sig­nif­i­cant positive impact to overall energy efficiency.

Energy Efficient Techniques in Renovations and New Construction

An Energy Efficient Roof

An energy efficient roof (cool roof) is designed to reflect sunlight and absorb less heat than a standard roof. Cool roofs reduce energy bills, improve indoor comfort, and may extend the service life of the roof. There are several tech­niques for creating a cool roof.

19. Cool roof coatings have special reflec­tive pigments or are white to reflect sunlight. A light-colored roof absorbs less than 50 percent of the solar energy, which reduces a roof’s tem­per­a­ture. In contrast, dark roofs absorb 90 percent of the solar energy.

20. Selecting a cool roof is dependent on the slope of a roof. For low-sloped roofs, with a pitch of 9.5 degrees or less, choose single-ply membranes that are light-colored and reflect the sun. Single-ply membranes are pre-fab­ri­cat­ed sheets that are rolled onto the roof and connected with mechan­i­cal fasteners, bonded with chemical adhesives, or kept in place with ballast (stones, gravel or pavers).

21. Painted metal roofs also satisfy low-slope cool roof require­ments for solar reflectance.

22. For steep sloped cool roofs, choose shingles. Cool shingle roofs are over­lap­ping panels made from wood, asphalt, metals, or polymers. The solar reflec­tive granules that coat the shingles keep the roof cool.

23.For steep sloped cool roofs, tiles, made from concrete, clay or slate, are also a good choice. Most tiles are naturally reflec­tive; however, treat­ments are available for tiles that are not naturally reflective. 

24. Green roofs are perfect for urban buildings with flat or shallow-pit roofs. Green roofs include anything from basic plant cover to a working garden.

Glazing Systems (windows, skylights, vents, and glass portions of doors) of an Energy Efficient Building

25. Purchase energy efficient windows appro­pri­ate for your climate zone. 

26. Installing storm windows can lower energy bills by up to $350 a year.

27. In the northern hemi­sphere, face major glazing areas south to take advantage of the solar heat gain in winter months when the sun is low. 

28. For warmer climates, limit south facing glazing and install overhangs or other shading devices over the south facing windows to prevent excessive heat gain during the summer.

29. In the southern hemi­sphere, north-facing windows are best.

30. Low-emis­siv­i­ty (low‑e) window glazing helps to control solar heat loss and gains. In fact, computer sim­u­la­tions indicate that advanced window glazing reduces the space cooling require­ments of new homes in warm climates by more than 40 percent.

31. Choose energy-efficient skylights that have estab­lished minimum ENERGY STAR® per­for­mance rating criteria by climate.

32. New exterior doors typically fit and insulate better than old doors. When selecting a new door, consider buying the most energy-efficient door possible according to energy per­for­mance ratings asso­ci­at­ed with the local climate and the build­ing’s design.

33. If you plan to keep an existing exterior door, a storm door is a good investment.

34. Improve an existing window’s energy effi­cien­cy with caulking and weather-stripping, and the use of thermal window treat­ments or coverings.

Ventilation in an Energy-Efficient Building

Proper ven­ti­la­tion is necessary for an energy-efficient home because air sealing tech­niques may trap pol­lu­tants (like formalde­hyde, volatile organic compounds, and radon). Ven­ti­la­tion also helps control moisture, which can cause mold growth and struc­tur­al damage.

35. An energy efficient building should include an energy recovery ven­ti­la­tion system. An energy recovery ven­ti­la­tion system provides con­trolled ven­ti­la­tion and minimizes energy loss by trans­fer­ring energy from con­di­tioned air going out to fresh incoming air.

36. Install localized exhaust fans above kitchen ranges and in bathrooms to create spot ven­ti­la­tion. Spot ven­ti­la­tion improves the effec­tive­ness of natural and whole-house ven­ti­la­tion by removing indoor air pollution and moisture.

37. While natural ven­ti­la­tion is the least expensive and most energy-efficient way to cool buildings, it works best when combined with spot ven­ti­la­tion, ceiling fans, and window fans. For large homes and buildings, whole buildings fans are a worth­while investment.

Heating and Cooling Systems of an Energy Efficient Building

Cooling, heating, and water heating account for the largest energy expenses in homes and com­mer­cial buildings. Incor­po­rat­ing energy efficient measures into a build­ing’s heating and cooling systems are essential to creating an energy-efficient structure.

38. Choose a high energy efficient heating, ven­ti­la­tion and air con­di­tion­ing (HVAC) system. For instance, the most efficient HVAC system is 95 percent efficient; meaning 5 percent of the energy produced is expelled. Consider replacing the HVAC every ten years.

39. Proper instal­la­tion of a new HVAC system is essential to an energy efficient building. Improp­er­ly installed HVAC systems can reduce a system’s effi­cien­cy by up to 30 percent.

40. Ensure that the fronts of vents are clear of obstruc­tions like furniture and paper. Blocked vents require as much as 25 percent more energy to dis­trib­ute air.

41. Install a pro­gram­ma­ble ther­mo­stat to manage periods of time where the heating and cooling can be turned down and up.

42. Change the air filter of the HVAC system as pre­scribed by the equipment man­u­fac­tur­er. Dirty filters slow down air flow and make the system work harder to keep a building warm or cool. Also, a clean filter prevents dust and dirt from building up in the system. Dust and dirt in an HVAC can lead to expensive main­te­nance and early system failure.

43. Maintain the HVAC annually to ensure its high effi­cien­cy, longevity, and the comfort level of the building.

44. To maintain an energy efficient building sealing the ducts that move air to-and-from the HVAC system is crucial. It is of par­tic­u­lar impor­tance to seal the ducts that run through the attic, crawl­space, unheated basement, or garage. Seal the seams and con­nec­tions of ducts with sealant (mastic) or metal-backed (foil) tape then wrap the ducts in insu­la­tion. The insu­la­tion will keep the ducts from getting cold in the winter and hot in the summer. 

High-Efficiency Water Heaters

Because heating water accounts for about 7 percent of com­mer­cial building energy use and 15 percent of home energy use, it is essential, for a high-effi­cien­cy building, to consider energy effi­cien­cy when selecting a water heating system. 

45. A tankless water heater heats water just when needed, elim­i­nat­ing energy lost during the standby operation. 

46. Install a high-effi­cien­cy storage (tank) water heater. High-effi­cien­cy water heaters use 10 to 50 percent less energy than standard models, saving energy and money on utility bills.

47. A high-effi­cien­cy heat pump water heater transfers energy from the sur­round­ing air to water in a storage tank. High-effi­cien­cy heat pump water heaters are most effective in warm climates with long cooling seasons.

48. A high-effi­cien­cy solar water heater can reduce operating costs up to 90 percent. 

Renewable Energy Sources for an Energy Efficient Building

49. Install grid-tied solar pho­to­volta­ic (PV) panels for a cost-effective form of renewable energy. Solar pho­to­volta­ic can power all the energy needs of a building including lighting, heating and cooling systems, appli­ances and hot water.

50. Install a small wind system either connected to the electric grid through your power provider or stand-alone (off-grid). A small wind electric system can lower electric bill by 50 to 90 percent. A variety of appli­ca­tions can use a small wind system, including water pumps.

51. A small hybrid” electric system combines home wind electric and home solar electric (pho­to­volta­ic or PV) tech­nolo­gies. A hybrid system is best in regions where peak times for wind and solar systems occur at different periods of the day and year.

52. On prop­er­ties with flowing water, Micro­hy­dropow­er is a simple and con­sis­tent form of renewable energy. A micro­hy­dropow­er system requires a turbine, water wheel, and pump to transform the energy of flowing water into rota­tion­al energy, and then into electricity.

Energy Efficient Lighting

53. Switch to light-emitting diode (LED) light bulbs. LED bulbs are energy-efficient, durable, and long-lasting. 

54. Install controls such as timers and pho­to­cells that turn lights off when not in use. Dimmers, when used to lower light levels, also save money and energy.

55. Use task lighting where suitable. A task light consumes far less energy than a typical overhead lighting fixture.

Energy Efficient Appliances

56. Select ENERGY STAR® refrig­er­a­tors because they use 15 percent less energy than non-qualified models. Also, refrig­er­a­tors with top-mounted freezers use 10 – 25 percent less energy than side-by-side or bottom-mount units.

57. Select ENERGY STAR® dish­wash­ers. ENERGY STAR® dish­wash­ers use less water and energy than required by federal standards. Dish­wash­ers are currently required to use 4.25 gallons of water per cycle or less.

58. Select com­mer­cial con­vec­tion ovens that have earned the ENERGY STAR® rating. ENERGY STAR® com­mer­cial ovens are about 20 percent more energy efficient than standard models.

59. An automatic electric ignition system on a natural gas oven or range can save gas because the pilot light is not con­tin­u­ous­ly burning.

60. Monitor flame color of natural gas ovens or ranges. A yellow flame indicates the gas is not burning effi­cient­ly and an adjust­ment is needed.

61. Keep ENERGY STAR® range-top burners and reflec­tors clean, so they will reflect the heat better and save energy.

62. Select clothes washers and dryers that have earned the ENERGY STAR® rating. 

Energy Efficient Electronics, Computers, and Office Equipment

63. Whether working in an office building or from home, utilizing energy efficient elec­tron­ics, computers, and office equipment can save building owners energy and money.

64. Purchase ENERGY STAR®-labeled office equipment which can save as much as half the elec­tric­i­ty of standard office equipment.

65. Use a laptop computer because laptops use much less energy than desktop computers.

66. Use sleep mode and power man­age­ment features on the computer.

67. Unplug elec­tron­ics when not in use because many elec­tron­ics continue to draw a small amount of power even when switched off. These little draws on energy can occur on most appli­ances that use elec­tric­i­ty: DVD players, TVs, stereos, computers, battery chargers, and kitchen appliances.

68. The U.S. Depart­ment of Energy’s (DOE) rec­om­mends the following guide­lines for turning off computers, monitors, printers, etc. to save energy and money. 

  • Turn off the monitor if not using the computer for more than 20 minutes.
  • Turn off both the CPU and monitor if not using the computer for more than 2 hours.

Other Ways to Make a Building More Energy Efficient

69. Incor­po­rate energy efficient land­scap­ing into the overall building design. For instance, shady land­scap­ing protects a building from direct sunlight during the summer and allows more sunlight to reach through windows during the winter. Addi­tion­al­ly, planting trees on the southern and western side of a building can keep the building cooler because it blocks sunlight from falling directly on the building during the winter; then, when after the trees lose their leaves, the trees allow more sunlight to reach the building.

70. Optimize system control strate­gies with occupancy sensors, CO2 sensors, and other air quality alarms.

71. Choose window treat­ments or coverings not only for dec­o­ra­tion but also for saving energy. For example, triple layer cellular shades can sig­nif­i­cant­ly reduce your utility bill and make the interior of a building more comfortable. 

Conclusion

While the upfront costs of making a building energy efficient may seem high, building owners soon recoup the extra cost through reduced utility and main­te­nance expenses. Also, incor­po­rat­ing energy efficient features into a building make it more valuable. In fact, a McGraw-Hill Con­struc­tion survey reported that new green building values were 7 percent greater than new non-green building projects. Green retrofit building values were 5 percent greater than non-green retrofit buildings. Today’s energy efficient tech­nol­o­gy is extensive and can be incor­po­rat­ed into all sizes and price ranges of new con­struc­tion and remodel projects. Visit Bautex™ Wall Systems for more ways to make a building more energy efficient.

Sources

Global warming refers to the modern-day rise in global tem­per­a­ture near the earth’s surface. The increase in tem­per­a­ture is due to increas­ing con­cen­tra­tions of green­house gases (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and flu­o­ri­nat­ed gases) in the atmos­phere. The expla­na­tion for global warming is straightforward. 

The sun’s energy falls on the earth as ultra­vi­o­let, visible (light), and infrared (heat) elec­tro­mag­net­ic energy. The earth absorbs some of the sun’s energy as thermal energy. The earth reflects another part of the sun’s energy (infrared heat) back into the atmos­phere where it either passes through the atmos­phere or is reflected back to the earth’s surface. Nitrogen and oxygen, which are the dominant gases in the atmos­phere, allow infrared heat to pass through the atmos­phere, while the green­house gases absorb infrared heat and redirect it back to the earth. The more green­house gases, the more heat is redi­rect­ed back to earth; hence the increase in global tem­per­a­tures near the earth’s surface. 

According to the National Climatic Data Center, before the Indus­tri­al Rev­o­lu­tion (about the year 1800), levels of carbon dioxide were about 280 parts per million by volume (ppmv); current levels are greater than 380 ppmv and increas­ing at a rate of 1.9 ppm per year since 2000. The burning of fossil fuels (coal, natural gas, and oil), solid waste, trees and wood products, and certain chemical reactions (e.g., man­u­fac­ture of cement) are respon­si­ble for the increase in green­house gases. Fur­ther­more, because plants absorb CO2 (thus remove it from the atmos­phere) as part of their bio­log­i­cal carbon cycle, defor­esta­tion and also lead to increased CO2 levels in the atmos­phere. Adverse impacts of global warming are extensive. A few of the impacts include rising sea levels due to increas­ing rates of glacial melting, more acidic oceans due to increas­ing carbon dioxide levels, and more frequent and severe weather events — like hurricanes.